Citrus
Nagami Kumquat
Citrus japonica 'Nagami' · Rutaceae
Also called: Oval Kumquat, Sour Kumquat
Nagami Kumquat (Citrus japonica 'Nagami') is a low-water citrus well suited to Tucson and the low desert. It thrives in full sun. Expect white, fragrant blooms in summer.
Nagami Kumquat at a glance
- Water use
- Low (established)
- Sun
- Full sun; in Tucson it benefits from light afternoon/filtered shade and protection from west-facing reflected heat on young trees.
- Mature size
- 8-12 ft tall and wide as a tree; often kept 6-8 ft as a shrub or in a large container.
- Growth rate
- Slow to moderate.
- Bloom
- White, fragrant, Blooms in summer (later than most citrus); fruit colors orange and ripens late winter into early spring, holding well on the tree.
- Cold hardiness
- The most cold-hardy citrus; semi-dormant in winter and tolerant to roughly 18-20°F, comfortably hardy in Tucson (USDA 9a-9b). Protect newly planted trees during hard freezes.
- Soil
- Well-drained sandy loam; tolerates Tucson's alkaline soils but performs best at pH 6.0-7.0 with added compost and good drainage. Avoid planting in turf or constantly wet ground.
- Native range
- Southern China and Southeast Asia; long cultivated. Not native to the Sonoran Desert.
- Best used as
- Edible ornamental fruit tree, Container/patio specimen, Marmalade and preserves, Small evergreen accent or informal hedge
- Wildlife
- Fragrant blooms attract bees; evergreen cover for birds.
- Toxicity
- Fruit edible (eaten whole, skin and all). Foliage/peel oils and thorns are non-toxic but can mildly irritate; generally considered safe around pets and children.
How to grow Nagami Kumquat in Tucson & the low desert
Watering
Deep, infrequent irrigation that wets the root zone to ~2 ft, then lets the top few inches dry. Every 7-10 days in summer heat, stretching to every 3-4 weeks in winter. Keep emitters out at the canopy dripline, not against the trunk; mulch to conserve moisture.
Fertilizer & nutrients
Use a citrus food (high nitrogen plus zinc, iron, manganese). Split annual nitrogen into thirds applied roughly Feb, May and Sept (UA Extension citrus schedule). Watch for iron/zinc chlorosis in alkaline soil; chelated micronutrients correct yellowing.
Pruning & care
Minimal. Remove dead, crossing or frost-damaged wood and any rootstock suckers below the graft in early spring after frost danger. Light shaping only; kumquats fruit on new growth.
Notes
Botanical name Citrus japonica is the accepted name (also sold as Fortunella margarita). 'Nagami' is the common oval, tart kumquat; the whole fruit is eaten, sweet rind with sour pulp. Excellent low-water, cold-tolerant citrus choice for Tucson and good in pots that can be moved during the coldest nights.
Sources: University of Arizona Cooperative Extension - Citrus Fertilization Chart for Arizona / Oranges for Southern Arizona (az1850); UCR Givaudan Citrus Variety Collection - Nagami kumquat (CRC 3877); AMWUA Landscape Plants for the Arizona Desert